A method and network for automatically determining primary and secondary session managers for an IP-enabled phone or other endpoint

A communication network comprises two or more endpoints, e.g. IP-enabled phones, and a cluster of two or more session managers. Each session manager comprises: a registrar operable to receive a registration request 406, e.g. a SIP registration request, from an endpoint and provide a set of session managers, comprising a primary and a secondary session manager, to the endpoint; and a redundancy determining engine operable to receive a pairing rule 408 associated with the registration request and information about two or more session managers. Based on the pairing rule the redundancy determining engine determines pairing factors 410, e.g. location of endpoints and location and loading of session managers, and applies the pairing rule to the pairing factor to determine a set of session managers 412 for the endpoint which it provides to the registrar and a data distributor which is operable to broadcast the set of session managers 416 to at least one other session manager in the cluster.